This section is from the book "Practical Sheet And Plate Metal Work", by Evan A. Atkins. Also available from Amazon: Practical Sheet And Plate Metal Work.

The marking out of the plates for the above will be similar to the former case; the only difference being in having separate slant-heights for the sides and ends. To obtain these the lengths a b and a c (Fig. 52) are each made equal to the vertical depth of the hopper; then c d and b e will give the lengths of the respective middle lines of the plates. The rest of the construction is as before.

If templates are required for the blades of the corner-angles, then these can be marked directly from the plate patterns, or their end-cuts transferred with the compasses. Thus, taking F as centre, describe an arc 1 0 2 to any radius; then, with the same radius, and F' as centre, mark the arc, 1' 0' 2'; cut off the arcs 0' 1' to equal 0 1, and 0' 2' to equal 0 2; join F' to 1' and 2'; so obtaining the rake for the ends of the angle-iron blades. The length F' A' will equal F A, and the cut on the bottom be parallel to the top.

The corner-angle r s t is shown marked out on the plan, the method of construction being exactly the same as in Fig. 51.

If it is desired to make a pattern for a smaller article, and to have the seams down the middle of the ends, then the marking out for this will be as shown in Fig. 52. Line A G = a g, A E = b e, and E F = e f, so giving the pattern for a side. The half-end must now be added thus: Set the compasses to c d, and with centre A, describe the arc passing through D; then, with the centre F, and radius / d, cut the former arc, so fixing the point D. Join F to D, and produce, making F H equal to f h, from the plan. Now draw A K parallel to F H, or square to AD, and cut off equal to a k. Another method, which is, perhaps, somewhat more convenient for workshop purposes, is shown on the other end of pattern, Set the compasses to a k, and, with G as centre, describe an arc (seen passing through L); then, with M as centre and h f as radius, draw the arc which passes through N. Draw a line to touch the two arcs, and on it drop perpendiculars from G and M.

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